Somewhere beneath the ocean right now, a fiber-optic cable no thicker than a garden hose is carrying your bank transaction, your video call, your search query. About 99% of all international internet traffic travels through submarine cables[s], and some estimates value the financial transactions flowing through them at $10 trillion per day[s]. The global subsea cable infrastructure is, by any measure, the most critical physical system underpinning the modern economy. And it is aging, under-protected, and increasingly under attack.
Subsea Cable Infrastructure: The Invisible Backbone
As of 2025, there are roughly 600 active and planned submarine cables spanning 1.48 million kilometers and connecting 1,600 landing stations worldwide[s]. These cables carry everything: email, streaming video, cloud computing, military communications, stock trades. Satellites, despite their visibility and cultural cachet, handle a negligible fraction of this traffic. The US Federal Communications Commission reports that satellites account for just 0.37% of all US international capacity[s].
The importance of subsea cable infrastructure cannot be overstated. When cables work, nobody thinks about them. When they break, millions of people notice within minutes.
200 Breaks a Year, and the Clock Is Ticking
Cable damage is not rare. On average, there are approximately 200 cable faults per year worldwide[s], roughly three to four per week[s]. The primary culprits are mundane: fishing trawlers and ship anchors account for about 70% of all damage[s]. Earthquakes, underwater landslides, and abrasion cause most of the rest.
What has changed is the repair timeline. According to ICPC data, repair response times have more than doubled over the past decade[s]. In 2023, there were 206 repairs across 136 jurisdictions, with the longest single repair taking 947 days[s]. A typical deep-sea repair takes two to eight weeks under favorable conditions[s], but permits, weather, and vessel availability can push that far longer.
A Repair Fleet Running on Fumes
Here is the core of the crisis. The global cable-laying and repair fleet is often tallied at roughly 60 to 62 specialized cable-laying and repair vessels[s]. Most were built around the year 2000, during the dot-com boom. Only eight of those ships are younger than 18 years old. Nineteen are over 30. One, the Finnish Telepaatti, was built in 1978[s].
By 2040, roughly two-thirds of cable maintenance ships will have reached the end of their service life[s]. In the same period, total cable kilometers deployed in the world’s oceans are projected to increase by 48%[s]. More cables, fewer ships to fix them. A TeleGeography and Infra-Analytics report estimates that sustaining current service levels will require an investment of roughly $3 billion: 15 replacement ships and 5 new ones[s].
New cable ships cost upwards of $100 to $150 million each and take several years to build[s]. The economics are brutal: narrow profit margins in the repair market give ship owners little incentive to invest in next-generation vessels. The subsea cable infrastructure is growing, but the ability to maintain it is not.
When Cables Become Targets
The threat landscape has shifted dramatically. In February 2024, a UK-owned cargo vessel struck by a Houthi missile sank in the Red Sea, damaging three major cables: Asia Africa Europe-1, Europe India Gateway, and SEACOM. The damage disrupted 25% of traffic between Asia, Europe, and the Middle East[s]. In September 2025, more Red Sea cable cuts degraded connectivity in India, Pakistan, and the broader Middle East[s].
In the Baltic Sea, a Chinese cargo vessel named the Yi Peng 3 left a Russian port in November 2024 and subsequently passed over two submarine cables connecting Sweden to Lithuania and Finland to Germany. Both cables were severed within hours[s]. Across 2024 and 2025, Recorded Future’s Insikt Group identified four incidents in the Baltic Sea involving eight distinct cable damages and five incidents around Taiwan involving five more[s].
These incidents have raised concerns about a potential new form of gray-zone conflict, in which states could target subsea cable infrastructure while maintaining plausible deniability through civilian vessels and anchor-dragging tactics. Investigations into the Baltic cases have not conclusively established state direction, but the pattern has put governments on alert[s].
Billions in New Cables, but the Same Old Bottleneck
Tech giants are pouring money into new cables. Meta’s Project Waterworth is a multi-billion dollar initiative to build over 50,000 kilometers of new cable spanning five continents[s]. Meta and its partners have developed more than 20 subsea cable systems over the past decade[s].
But new capacity does not solve the maintenance problem. More cables mean more potential fault points, more repair demand, and more strain on an already insufficient fleet. The subsea cable infrastructure is expanding in ways that may outpace the world’s ability to keep it functioning.
What This Means for You
If you live in a well-connected country with multiple redundant cable routes, a single break is an inconvenience: some latency, briefly slower speeds. But for the billions of people in regions with limited cable diversity, including much of Africa, the Pacific Islands, and parts of Southeast Asia, a cable fault can mean days or weeks of degraded connectivity, disrupted banking, and inaccessible cloud services[s].
The global economy built itself atop these thin glass threads without building the safety net to match. The question is no longer whether the subsea cable infrastructure will face a major, cascading failure. It is when, and whether the world will be ready.
The global subsea cable infrastructure carrying an estimated 99% of international data traffic[s] and facilitating roughly $10 trillion in daily financial transactions[s] is converging on a systemic crisis driven by three compounding factors: aging physical plant, an insufficient maintenance fleet, and an escalating threat environment that now includes suspected state-linked gray-zone activity and a rising risk of sabotage.
The Physical Layer: Subsea Cable Infrastructure by the Numbers
As of April 2025, there are 597 subsea cables in operation or under construction, up from 559 in 2024[s]. The Internet Society counts 570 commercial cables with 81 planned[s]. These systems span approximately 1.48 million kilometers and connect 1,600 landing stations[s]. Three manufacturers dominate the supply side: France’s Alcatel Submarine Networks, the US’s SubCom, and Japan’s NEC, with China’s HMN Technologies playing an increasing role[s].
Submarine cables are engineered for a minimum 25-year design life, referring to the wet plant components’ specified failure rate over that period[s]. In practice, the average lifespan of cables retired since 2010 is approximately 17 years, well below the design threshold[s]. A significant portion of the current cable infrastructure was laid during the dot-com boom around 2000 and is now approaching or exceeding its design maturity[s].
Fault Rates and Repair Capacity: The Diverging Curves
ICPC data shows an average of 199 cable faults per year from 2010 to 2024, a rate that has remained remarkably stable despite a substantial increase in total route mileage[s]. This per-kilometer improvement reflects better geophysical surveys, improved armoring, deeper burial techniques, and enhanced public awareness of cable locations. Fishing and anchoring incidents account for 86% of all faults[s].
The maintenance fleet tells a different story. Approximately 80 vessels globally are dedicated to maintaining and expanding submarine cable infrastructure[s], with the top five operators being Global Marine Systems, Orange Marine, SubCom, Alcatel Submarine Networks, and Optic Marine Services. The fleet skews old: most vessels are between 20 and 30 years of age, 19 exceed 30 years, and only eight are younger than 18[s].
The repair capacity gap is quantifiable. In 2023, the ICPC recorded 206 repairs across 136 jurisdictions[s]. Repair response times have more than doubled over the past decade. The longest single repair took 947 days. Without fleet expansion, Recorded Future assesses that median restoration times will exceed the current 40-day benchmark[s]. By 2040, approximately two-thirds of cable maintenance ships will have reached end-of-life, coinciding with a projected 48% net increase in deployed cable kilometers[s]. TeleGeography estimates the gap requires $3 billion in investment: 15 replacement and 5 additional vessels[s].
The Threat Environment: From Accidental to Adversarial
Insikt Group’s analysis of 44 publicly reported cable damages in 32 distinct groupings during 2024 and 2025 reveals a shifting threat profile. Unknown causes accounted for 31% of damages, followed by anchor dragging at 25% and seismic or natural phenomena at 16%[s]. Three incidents caused prolonged outages with significant economic impact:
- Red Sea, February 2024: The sinking of a Houthi-struck vessel damaged AAE-1, EIG, and SEACOM, disrupting 25% of Asia-Europe-Middle East traffic[s].
- West Africa, March 2024: An underwater rockslide severed four cables (WACS, ACE, MainOne, SAT-3), disrupting connectivity in at least 13 countries[s].
- South Africa, May 2024: SEACOM and EASSy damage caused internet outages across 12 East African countries[s].
The Baltic Sea incidents present a particularly concerning pattern. In November 2024, two cables connecting Sweden-Lithuania and Finland-Germany were severed within hours of each other, and the Chinese-flagged Yi Peng 3 came under investigation after passing near the damage sites[s]. The vessel had departed a Russian port, and at least four of the Baltic and Taiwan incidents involved Russia- or China-linked vessels operating under suspicious circumstances, though public attribution remains difficult[s]. Europe’s redundant subsea cable infrastructure limited the impact: Cloudflare reported “little-to-no observable impact” on affected countries[s]. A similar incident against a less redundant network could be devastating.
Redundancy Asymmetry and Route Concentration
The vulnerability of subsea cable infrastructure is not uniform. Well-connected regions like Northern Europe can absorb multiple cable losses without measurable service degradation. But the Red Sea corridor, where multiple cables converge through narrow straits, represents a critical concentration of risk. Similarly, countries dependent on one or two cables, such as Tonga, the Matsu Islands, and several West African nations, face existential connectivity risk from single-point failures.
When Taiwan’s Matsu Islands lost both connecting cables in February 2023, a backup microwave system restored only an estimated 5% of lost bandwidth. Full internet access was not restored until April 2023[s]. Satellite capacity remains a stop-gap at best: the FCC reports satellites carry just 0.37% of US international capacity[s].
Investment Paradox: New Capacity vs. Maintenance Deficit
The hyperscaler-driven cable boom is adding enormous capacity. Meta’s Project Waterworth will span over 50,000 kilometers across five continents using 24 fiber pairs, the highest-capacity technology available[s]. But the economics of maintenance remain broken. New cable ships cost $100 to $150 million, take years to build, and operate on thin margins. Ship operators are prioritizing hyperscaler installation contracts over maintenance capacity[s].
The US has created a Cable Security Fleet program consisting of two commercial vessels contracted for national emergencies[s]. The EU’s 2025 Joint Communication on Cable Security represents a more comprehensive approach, emphasizing cross-border coordination, monitoring, and public-private partnerships[s]. Whether these policy frameworks can close the gap before the next major cascading failure remains the central question for global subsea cable infrastructure resilience.
The Structural Problem
The fundamental tension is architectural. Subsea cable infrastructure evolved as a private-sector, market-driven system. The cables are owned by consortia of telecommunications companies and, increasingly, by hyperscalers like Meta and Google. The repair fleet is commercially operated. Governments have only recently begun treating these systems as critical infrastructure on par with energy and transportation networks[s].
This governance gap means that the system optimizes for capacity deployment, where the money is, rather than maintenance resilience, where the risk is. The result is a global digital economy balanced on a foundation of aging cables, aging ships, and aging assumptions about the threat environment. The subsea cable infrastructure problem is not a future risk. It is a present vulnerability, compounding with every cable laid and every ship year lost.
